Sliding Pi - Ivars Peterson (MathTrek)
"The entrance to the Downsview subway station in Toronto presents visitors with a striking vista. A vast mosaic of square tiles sweeps across a curved wall, inviting viewers to trace its lines and ponder intriguing irregularities
in its color scheme
...more>>

Sloan Digital Sky Survey
The astronomical surveys of the Sloan Digital Sky Survey (SDSS) have "obtained deep, multi-color images covering more than a quarter of the sky and created 3-dimensional maps containing more than 930,000 galaxies and more than 120,000 quasars." SDSS's
...more>>

Slocum Puzzles - Jerry Slocum
Puzzle collector and author's site. Features puzzle descriptions, shop, descriptions of books written by Slocum and collaborators, and a history of Slocum's famous Puzzle Parties.
...more>>

Smarandache Notions - J. Castillo
A journal for papers related to the work of Florentin Smarandache, who in the 1960s proposed some new geometries: Non-Geometry, Counter-Projective Geometry, Anti-Geometry, and Paradoxist geometry, which would generalize and unite Euclid, Lobachevsky/Bolyai/Gauss,
...more>>

Smarandache Paradoxist Geometry - Chimienti, Bencze
Uniting Euclidean, Lobachevsky-Bolyai-Gauss, and Riemannian geometries. Smarandache geometries are partially Euclidean and partially Non-Euclidean. It is based on the first four of Euclid's postulates, but the fifth postulate is
replaced so that there
...more>>

Smithsonian Institution
An independent trust instrumentality of the United States holding some 140 million artifacts and specimens in its trust for "the increase and diffusion of knowledge," and a center for research dedicated to public education, national service, and scholarship
...more>>

Soap Films and Grid Walks - Ivars Peterson (MathLand)
A simple, physical demonstration of a mathematical truth can produce a lasting impression - one that inspires new questions and speculations. For Christopher C. Chang, a student at Henry M. Gunn Senior High School in Palo Alto, Calif., and one of 40 finalists
...more>>

Social Actuary - Social Actuary
The Social Actuary community allows actuaries to: create a user profile; connect with other actuaries around the world to discuss exams, study habits, careers and much more via the Forums; display exam and destination progress via user profile; create
...more>>

Society for Industrial and Applied Mathematics (SIAM)
SIAM was founded in 1951 to advance the application of mathematics to science and industry, promote mathematical research that could lead to effective new methods and techniques for science and industry, and to provide media for the exchange of information
...more>>

Society for Mathematical Biology
A forum for discussion of research in biology, mathematical biology, and mathematics applied to or motivated by biology - interdisciplinary research such as biophysics, computational biology, and many other similar realms. Information on membership and
...more>>

Society for Risk Analysis (SRA)
A multidisciplineary, international open forum for those interested in risk analysis, broadly defined to include risk assessment, characterization, communication, management, and policy. Interests include risks to human health and the environment, both
...more>>

Society of Actuaries
Actuaries are professionals trained in mathematics, statistics, and economic techniques that allow them to put a financial value on future events. This skill is of great value to insurance companies, investment firms, employee benefits consulting firms,
...more>>

Society of Manufacturing Engineers (SME)
The premier source of learning and knowledge for the manufacturing community. An international professional society dedicated to serving its members and the manufacturing community through the advancement of professionalism, knowledge, and learning. Founded
...more>>

Soddy's Formula - Pat Ballew
Descartes' Circle Theorem, an example of giving the credit to the wrong person. The formula is about the relation of the radii of four mutually tangent circles and is sometimes called the Kissing Circles Theorem: if four circles are all tangent to each
...more>>

Sofist India - Sofist India
A software company that specializes in developing off-the-shelf products and components (assemblies) using Microsoft .NET technology. The company also develops and maintains software packages and develops web sites. Its expertise lies in the fields of
...more>>

Software's Origin - Ivars Peterson (MathTrek)
Librarian Fred R. Shapiro of the Yale Law School in New Haven, Conn., searched for the word software among scholarly journals electronically archived in the JSTOR database and found that the term software used to describe computer programs dates back
...more>>

Soler's Fractal Site
Fractal galleries of images made using Tierazon and other programs, links, downloads of fractal-generating programs, and articles on fractals.
...more>>

Solitaire-y Sequences - Ivars Peterson (MathTrek)
Solitaire on the computer screen - called Klondike or Idiot's Delight, this form of solitaire has resisted mathematical analysis. Partly because Klondike involves player choice, no one has yet been able to construct a mathematical model of the game from
...more>>